Corrosion inhibitors

ABSTRACT

The reaction product of an α,β-ethylenically unsaturated aldehyde with an organic amine further reacted with a carboxylic acid, organic halide or an epoxide containing compound is employed as corrosion inhibitors in a process for preventing corrosion of ferrous metals in contact with corrosive brine, oil and gas well fluids.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No.843,521 filed Mar. 24, 1986, now abandoned, which is acontinuation-in-part of application Ser. No. 691,329, filed Jan. 14,1985, now abandoned.

FIELD OF THE INVENTION

The present invention relates to new and useful corrosion inhibitors andin particular to corrosion inhibitors which materially reduce theeffects of attack of reactive materials on metals of construction.

BACKGROUND OF THE INVENTION

In oil producing applications, metal tubing, sucker rods, valves,screens, coatings, pumps, and the like are subjected to the action ofextremely corrosive fluids and gases. Such sweet and/or sour corrosivecompositions can contain dissolved materials such as hydrogen sulfide,sulfur dioxide, carbon dioxide, oxygen, mineral acids, organic acids,and the like, as well as mixtures thereof.

Numerous processes for inhibiting the corrosion of metals caused uponexposure to corrosive oil and gas well fluids have been proposed. See,for example, U.S. Pat. Nos. 2,643,977 and 3,077,454. Unfortunately, suchprocesses are not effective under the conditions of high temperaturesand pressures experienced by metal equipment in extremely deep oil andgas wells. Such conventional corrosion inhibitors can have a tendency todegrade, volatilize, or polymerize causing formation damage and/orinadequate corrosion protection. In view of the deficiencies of theprior art, it would be highly desirable to provide a corrosion inhibitorwhich is easily prepared and can be effectively employed under very hightemperature and pressure conditions.

SUMMARY OF THE INVENTION

The present invention pertains to a new composition of matter whichcomprises the product resulting from thermally treating, at atemperature of at least about 180° C. for a time sufficient to renderthe resultant thermally treated product thermally stable at atemperature at least 25° C. above that of the untreated product, theproduct resulting from reacting, in the presence or absence of asuitable solvent.

(A) at least one aliphatic α,β-monoethylenically unsaturated aldehydehaving from about 3 to about 6 carbon atoms; and

(B) at least one organic diamine represented by the formula ##STR1##wherein R is a divalent saturated C₂ to C₄ aliphatic hydrocarbon group;each R¹ and R² is independently hydrogen or a saturated alkyl amino oran alkyloxy group containing from 2 to about 4 carbon atoms or when twoadjacent R² groups are taken together, they form a bridging alkyleneradical containing 2 carbon atoms such that the R group containing 2carbon atoms and two adjacent R² groups and two nitrogen atoms form aheterocyclic ring containing 4 carbon atoms and 2 nitrogen atoms; x hasa value from 1 to about 8 and

wherein components (A) and (B) are employed in a mole ratio of (A) to(B) of from about 1:1 to about 1:6.

Another aspect of the present invention pertains to a new composition ofmatter which is the product resulting from reacting at a temperature offrom about 25° C. to about 250° C. for a time sufficient to render thereaction complete as determined by halide or residual acid numbertitrations.

(I) the product resulting from thermally treating, at a temperature ofat least about 180° C. for a time sufficient to render the resultantthermally treated product thermally stable at a temperature at least 25°C. above that of the untreated product, the product resulting fromreacting, in the presence or absence of a suitable solvent,

(A) at least one aliphatic α,β-monoethylenically unsaturated aldehydehaving from about 3 to about 6 carbon atoms; and

(B) at least one organic diamine represented by the formula ##STR2##wherein R is a divalent saturated C₂ to C₄ aliphatic hydrocarbon group;each R¹ and R² is independently hydrogen or a saturated alkyl amino oran alkyloxy group containing from 2 to about 4 carbon atoms or when twoadjacent R² groups are taken together, they form a bridging alkyleneradical containing 2 carbon atoms such that the R group containing 2carbon atoms and two adjacent R² groups and two nitrogen atoms form aheterocyclic ring containing 4 carbon atoms and 2 nitrogen atoms; x hasa value from 1 to about 8 and

wherein components (A) and (B) are employed in a mole ratio of (A) to(B) of from about 1:1 to about 1:6; and

(II)

(A) at least one saturated or unsaturated, cyclic or acyclic aliphaticmono- or polycarboxylic acid having from about 2 to about 50 carbonatoms; or

(B) at least one saturated or unsaturated, cyclic or acyclic aliphaticalkyl monohalide or alkyl polyhalide having from about 2 to about 50carbon atoms; or

(C) a combination of (A) and (B);

wherein components (I) and (II) are employed in quantities which providefrom about 0.4 to about 1, suitably from about 0.55 to about 0.85, moresuitably from about 0.65 to about 0.75 equivalent of carboxyl and/orhalide groups from component (II) for each theoretically active aminohydrogen atom contained in component (I).

The present invention provides corrosion protection to metalcompositions exposed to corrosive gases and/or liquids at hightemperatures and pressures, such as are experienced in deep oil and gaswells.

DETAILED DESCRIPTION OF THE INVENTION

The corrosion inhibitors of the present invention act to protect metalcompositions from corrosive effects of fluids, liquids and/or gases,which are present in brine, oil and gas wells in either surfaceequipment and piping or in down hole well environments. Metalcompositions typically include steel, iron, ferrous alloys, and otheralloys of which typical sucker rods, valves, pumps, etc. are comprised.

The α,β-ethylenically unsaturated aldehydes useful herein can begenerally represented by the formula: ##STR3## wherein each R, R¹ and R²are independently hydrogen, an alkyl group, or a substituted alkyl groupwherein said substituent groups include, for example, halo, alkoxy andamino groups. Examples of suitable α,β-monoethylenically unsaturatedaldehydes are disclosed in U.S. Pat. No. 3,459,710 which is incorporatedherein by reference. Other suitable aldehydes include, for example,acrolein, crotonaldehyde and hexenal. The preferred α,β-ethylenicallyunsaturated aldehyde is acrolein, or mixtures thereof with otheraldehydes.

The organic polyamines of this invention can include those organicdiamines of the type disclosed in the aforementioned U.S. Pat. No.3,459,710 as well as those polyamines disclosed in U.S. Pat. No.4,292,413 which are incorporated herein by reference. Other polyaminesinclude, for example, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine, polyoxypropyleneamine, iminobispropylamine,aminoethylethanolamine, and the like as well as mixtures thereof. Inaddition, monofunctional amines that can be utilized includediglycolamines, dodecylamine, cocoamine, hexadecylamine, octadecylamine,tallowamine, and the like. Of the foregoing polyamines, those polyaminescontaining at least one primary amine are preferred; with thosepolyamines capable of forming imidazolidine or hexahydropyrimidinemoieties or substituted moieties thereof being most preferred.Polyamines can be partially alkoxylated or partially polyalkoxylated solong as they contain at least one active amine hydrogen. Preferredpolyamines are ethylenediamine and propylenediamine. Suitable polyaminesalso include the aminated polyoxyalkylene polyols.

The compounds comprising a functionality and/or functionalities capableof undergoing a reaction, quaternization or neutralization with an amine(i.e., substituent compounds) include, for example, compounds containingcarboxylic acid moieties, organic halide moieties, epoxide moieties, andthe like. For example, a carboxylic acid moiety can react with an amineto form a salt, amide or amidine-type linkage. Most preferably,substituent compounds include the polycarboxylic acids, organicpolyhalides and polyepoxides. Such compounds are capable of introducingdesired crosslinking to the product. Monocarboxylic acid compounds,organic monohalides and monoepoxide compounds can be employed. Examplesof suitable carboxylic acids include acetic acid, benzoic acid, phthalicacid, terephthalic acid, octanoic acid, myristic acid, palmitic acid,oleic acid, isostearic acid, capric acid, caprylic acid, lauric acid,tall oil fatty acids, napthenic acids, dimer acids, trimer acids andsimilar mono- and polycarboxylic acids. Other suitable acids aredisclosed in U.S. Pat. No. 4,339,349, which is incorporated herein byreference. Examples of suitable organic halides are disclosed in U.S.Pat. 4,315,087 which is incorporated herein by reference. Examples ofsuitable mono- and polyepoxides include epoxidized vegetable oils suchas epoxidized linseed oil, epoxidized carboxylic acids such asepoxidized oleic acid, the glycidyl ethers, and the like. Other suitableepoxide compounds are disclosed in U.S. Pat. No. 4,292,413 which isincorporated herein by reference. Other suitable compounds comprising afunctionality or functionalities capable of undergoing a reaction,quaternization or neutralization with an amine include, for example,inorganic acids, aldehydes, alkylene oxides, cyanides, nitriles, sulfurcontaining compounds such as mercaptans, and the like. Preferably, thesubstituent compound has a predominantly hydrophobic character.

Products used in this invention are preferably prepared by firstreacting the organic polyamine with the α,β-ethylenically unsaturatedaldehyde. Preferably, the reaction is carried out in an inert atmosphereand at a temperature between about 0° C. and about 150° C. The choice ofinert solvent is generally dependent upon the boiling point of thepolyamine, the solubility of the polyamine and the solubility of theresulting oligomer or polymer. Advantageously, the solvent is one inwhich both the monomers and resultant oligomer are soluble. Suitablesolvents include methanol, ethanol, butanol, benzene, water, dioxane,dimethylformamide, tetrahydrofuran, and the like.

Preferably one mole of polyamine is reacted with 0.1 to 1.0 mole ofunsaturated aldehyde. Preferably, the organic polyamine is dissolved ina suitable solvent in a reaction vessel. A solution of the unsaturatedaldehyde and suitable solvent is then contacted with the polyaminesolution, preferably in a slow manner. The reaction mixture can becooled or heated. Solvent can be removed by distillation. Preferably, asolvent, such as isopropanol can be added to the reaction mixture inorder to create an azeotropic mixture for removing solvent andby-product.

Oligomer or polymer products usually have an average molecular weightless that about 1,000 and are obtained from the reaction ofα,β-ethylenically unsaturated aldehydes with organic polyamines. Theoligomers or polymers within the scope of this invention comprisecompounds that can comprise vinyl, imine, enamine, ether, and hydroxylfunctional groups. The reaction of an amine containing piperazine ringswith an α,β-ethylenically unsaturated aldehyde introduces piperazinerings into the constituents of the product. The reaction of the carbonylof α,β-monoethylenically unsaturated aldehyde with a primary amine formsan imine which readily cyclizes if labile (where the term "labile" is asdefined in U.S. Pat. No. 4,315,087, which is incorporated herein byreference) amine hydrogens are available, preferably in the gamma ordelta position relative to the nitrogen of the imine. An imidazolidinering is formed from the reaction of the carbonyl of anα,β-monoethylenically unsaturated aldehyde with an ethylenepolyaminewhile a hexahydropyrimidine ring is formed from the reaction of thecarbonyl of an α,β-monoethylenically unsaturated aldehyde with apropylenepolyamine. Some of the possible constituents of the oligomersformed from the reaction, prior to thermal rearrangement, of, forexample, acrolein with ethylenediamine are believed to be represented bythe following structures, although the applicants do not wish to belimited by this theory: ##STR4##

The thermal treatment is usually conducted by heating the oligomer orpolymer from the reaction of α,β-ethylenically unsaturated aldehyde withan organic polyamine while stirring in air or an inert atmosphere suchas, for example, nitrogen, helium, neon, xenon, argon, mixtures thereofand the like. The temperature required to achieve the increase inthermal stability depends upon the particular oligomer or polymer beingtreated. However, a temperature of at least about 180° C., preferablyfrom about 190° C. to about 350° C. is usually required. In someinstances, lower temperatures could produce the desired increase inthermal stability. The oligomer or polymer is heated for a period oftime to sufficiently rearrange the original oligomers or polymers suchthat the resultant product has an increase in thermal stability of atleast 25° C. above that of the product prior to heat treatment. Theperiod of time in which the oligomer or polymer is heated can range fromabout 10 minutes to about 48 hours. The preferred period of time forthermally rearranging the oligomer or polymer is 30 minutes to 2 hours.In the case where the oligomer or polymer results from the reaction ofacrolein with an ethylenepolyamine, pyridines and pyrazines having alkylsubstituents are formed and are evolved or reside with the finalproduct. Also, the imine concentration increases during thermalrearrangement. Generally, the thermally rearranged oligomer or polymeris more thermally stable than the original oligomer or polymer. Thepreferred atomosphere for stirring the oligomer or polymer duringthermal rearrangement is nitrogen.

The product which is isolated can be contacted with the compoundcomprising a functionality or functionalities capable of undergoing areaction, quaternization or neutralization with an amine. The previouslydescribed product is dissolved or dispersed in a suitable solvent andcontacted with the substituent compound which is also dissolved in asuitable solvent. The amount of substituent compound which is employedcan vary such that about 1 to about 100 percent of the available aminohydrogens of the polyamine/unsaturated aldehyde product can be reactedwith reactive functionalities of the substituent compound. Thisresulting product can, if desired, be isolated using techniques such asdistillation to remove by-products and solvent.

The resulting thermally treated product can be employed as a corrosioninhibitor as are conventional corrosion inhibitors. Generally, theproduct can be employed in corrosion inhibitor formulations as are knownin the art. For example, the product can be dispersed or dissolved in asuitable carrier liquid or solvent such as water, alcohols, aromatic andaliphatic hydrocarbons, and the like, or mixtures thereof. Otheradditives include demulsifiers, water wetting agents, surfactants,viscosifiers, commingled gases, defoamers, other corrosion inhibitorssuch as polymeric materials and salts, organic and inorganic acids, ironcontrol agents, sequestering and/or chelating agents, phosphates,quaternaries, amine salts, and the like. For example, surface activeagents are used to assure complete dispersion of active ingredientsthroughout the corrosion inhibitor composition and thus provide a bettercontact of the corrosion inhibitor with the surface of the metalcompound which is being protected. The corrosion inhibitors of thisinvention form films on metal surfaces at least as readily as thoseknown film forming corrosion inhibitors.

The corrosion inhibitor of this invention is employed in a functionallyeffective amount. That is, any quantity of corrosion inhibitor whichwill provide some degree of inhibition of corrosion is sufficient.Typical amounts of corrosion inhibitor which are employed in an oiland/or gas well treatment can range from about 5 to about 100,000 ppmbased on the weight of corrosive well fluids in contact with the metalcompositions which are to be protected. For continuous treatment, theamount of inhibitor can range from about 5 to about 2,000 ppm, suitablyfrom about 50 to about 1,000, most suitably from about 100 to about 200ppm based on the weight of corrosive well fluids in contact with themetal compositions which are to be protected. For batch treatment, theamount of inhibitor can range from about 10,000 to about 100,000,suitably from about 40,000 to about 60,000 ppm based on the weight ofcorrosive well fluids in contact with the metal compositions which areto be protected. Amounts of corrosion inhibitor in excess of 50-60,000ppm can provide additional corrosion inhibition but at increasedexpense.

The corrosion inhibitors of this invention are highly stable to hightemperatures and high pressures. Typically, corrosion inhibitors areemployed in applications where temperatures range from about 100° F.(37.7° C.) to in excess of about 500° F. (260° C.), depending upon thecomposition of the polymer product. The corrosion inhibitors of thisinvention are especially useful at temperatures ranging from 300° F.(148.8° C.) to about 450° F. (232.2° C.).

The corrosion inhibitors of this invention inhibit corrosion to metalcompositions used in down hole applications, preferably in excess of 80percent corrosion protection. The corrosion inhibitors advantageouslyinhibit corrosion to metal compositions at elevated temperaturesexceeding 250° F. in oil and gas well applications. Useful applicationsinclude oil and/or gas well drilling, completion, workover, stimulation,transfer, processing and storage applications.

The following examples are presented to further illustrate but not limitthe scope of this invention.

EXAMPLE 1 A. Preparation of Acrolein/Ethylenediamine Oligomer at a MolarRatio of 1/1 Respectively

Acrolein is distilled in the presence of 358 ppm and 379 ppm ofhydroquinone in the boiling and receiving flasks, respectively. Asolution of distilled acrolein was prepared by mixing 282.1 grams (g) (5moles) acrolein with about 155 g methanol.

Into a reactor equipped with stirrer, thermometer, condenser, andaddition funnel with nitrogen inlet tube was placed a solution of 300 g(500 moles) ethylenediamine and about 510 g methanol. The reactorcontents were stirred under nitrogen atmosphere while being held at atemperature of about 4° C.

The acrolein solution was added to the reactor over a period of 160minutes (9600 s) at such a rate that the rise in temperature did notexceed 23° C. The mixture was subject to rotary evaporation at 100° C.An amount of isopropanol was added to the mixture and said mixture wasagain subject to rotary evaporation at 100° C. The product was ayellowish viscous liquid.

B. Thermal Treatment of Oligomer

Into a one liter reactor equipped with a condensing assembly, stirrer,thermometer, addition funnel, and nitrogen inlet tube was placed 210 gof the oligomer product from A above. The condensing assembly consistedof a Dean Stark trap, cold water condenser and dry ice-acetone coldfinger. The reactor contents were stirred under nitrogen atmosphere at125° C. for 60 minutes (3600 s). Then the reactor contents were heatedat 10° C. increments at 60 minute intervals up to 250° C. Overhead andbottom samples were caught at each 10° C. interval.

Infrared spectra of the bottom sample indicated the oligomer product hadundergone thermal rearrangement. The infrared spectra at 125° C. showedbands at 1655, 1630 and 1600 cm⁻¹. The band at 1655 cm⁻¹ was assigned toC═N stretch. The absorption at 1630 cm⁻¹ was attributed to C═C stretch.The absorption at 1655 and 1630 cm⁻¹ increased upon heating the polymerproduct up to 190° C. Above 190° C., the band at 1600 cm⁻¹ was thepredominant absorption of the three bands.

The infrared spectra at 125° C. also showed absorption bands at 3270,2940, 2800, 1260 and 900 cm⁻¹. The absorption band at 3270 cm⁻¹ wasassigned to N-H stretching vibration of a secondary amine. Above 190° C.a broad absorption band at 3400 cm⁻¹ replaced the 3270 cm⁻¹ band. Theabsorption bands at 2940 and 2800 cm⁻¹ were assigned to C-H stretch. At125° C., these bands were of similar intensity. Above 190° C., the bandat 2940 cm⁻¹ was slightly more intense than the band at 2800 cm⁻¹. Above190° C., the absorption at 1260 and 900 cm⁻¹ disappeared.

Overhead samples collected in the Dean Stark trap were analyzed byelectron impact mass spectroscopy. Methylpyridine was identified only inoverhead samples collected at and above 135° C. Ethanamine, pyrazine,methylpyrazine, ethylpyrazine, dimethylpyridine, ethylpyridine,trimethylpyridine, and ethylmethylpyridine were identified along withmethylpyridine in the overhead fraction collected at 250° C.

The reactor bottom samples were analyzed with methane chemicalionization probe mass spectroscopy. [M+1]⁺ fragments corresponding tothe molecular weight of methylpyridine was observed only in the bottomsamples collected at and above 170° C. [M+1]⁺ fragments corresponding tothe molecular weights of C₂ -pyrazine, C₃ -pyrazine, C₄ -pyrazine and C₅-pyrazine were present in addition to that corresponding tomethylpyridine in the bottom samples collected at and above 180° C. Thebottom sample collected at 250° C. was a dark brown hard solid at roomtemperature that had a distinct pyridine odor.

The number average molecular weight (Mn) and weight average molecularweight (Mw) of the thermally treated product was determined by gelpermeation chromatography with methanol as the eluent. Monoethyleneglycol and E-200 polyglycol served as standards. Between 125°-190° C.,the Mn varied between 196≧235 and the Mw varied between 394-423. Between200°-250° C. the Mn varied between 100-130 and Mw varied between234-280.

EXAMPLE 2 A. Preparation of Acrolein/Mixture of Tetraethylenepentamine,Pentaethylenehexamine, Hexaethyleneheptamine Oligomer

Into a jacketed reactor equipped with a mechanical stirrer, thermometer,condenser, and addition funnel is placed a solution containing 771 grams(3.15 moles) of a polyalkylene polyamine product having an averagemolecular weight higher than tetraethylenepentamine commerciallyavailable from The Dow Chemical Company as Ethyleneamine E-100 and 495grams of anhydrous methanol. The reactor contents were stirred undernitrogen atmosphere while cooled to 3° C. A solution of distilledacrolein was prepared by mixing 282 grams (5.03 moles) of acrolein with323 grams of anhydrous methanol. The acrolein solution was added to thereactor using an addition funnel over a period of 250 minutes (15,000s). After reaction completion, the mixture was subjected to rotaryevaporation at 100° C. An amount of isopropanol was added to the mixtureand again subjected to rotary evaporation. The resultant product was anamber colored viscous liquid.

B. Thermal Treatment of Oligomer

Into a one liter reactor requipped with a condenser assembly, mechanicalstirrer, nitrogen inlet tube, and thermometer was placed 139 grams ofthe oligomer product from A above. The condenser assembly consisted of aDean Stark trap and chilled glycol condenser. The reactor contents werestirred under the nitrogen atmosphere at 100° C. for 1 hour (3600 s).The reactor contents were heated incrementally at 60 minute intervals to350° C. Overhead and bottom samples were caught at each interval.

Overhead samples collected in the Dean Stark trap were analyzed byelectron impact mass spectroscopy. Methylpyridine, ethylpyridine,dimethylpyridine and methylethylpyridine were identified in the overheadfractions collected between 150° and 300° C. Methylpyridine was the mostconcentrated of these constituents. Dimethylpyrazine,methylethylpyrazine and C₄ -pyrazine were identified in the overheadfractions collected at and above 300° C.

EXAMPLE 3 Thermal Stability

The thermal stability of the products of this invention was determinedby different scanning calorimetry (DSC) scan of various samples using aDuPont Model 1090 Thermoanalyzer. In the differential scanningcalorimetry analysis, the samples were placed in an aluminum pan andprogrammed from 25° to 500° C. at 10° C./min. with a nitrogen purge. Thesamples tested were the thermally rearranged acrolein/ethylenediamineoligomers and the acrolein/mixture of tetraethylenepentamine,pentaethylenehexamine and hexaethyleneheptamine oligomers prepared asdescribed in Examples 1 and 2, respectively. Results for the thermallyrearranged acrolein/ethylenediamine oligomers prepared in Example 1 aregiven in Table I.

                  TABLE I                                                         ______________________________________                                        Thermal       Initial                                                         Treatment     Decomposition                                                   Temperature   DSC                                                             ______________________________________                                        NONE*         200° C.                                                  125*          160° C.                                                  135*          150° C.                                                  160*          200° C.                                                  170*          210° C.                                                  180           280° C.                                                  250           300° C.                                                  ______________________________________                                         *Not an example of this invention.                                       

Results for the thermally rearranged acrolein/mixture oftetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamineoligomers as prepared in Example 2 are given in Table II.

                  TABLE II                                                        ______________________________________                                        Thermal       Initial                                                         Treatment     Decomposition                                                   Temperature   DSC                                                             ______________________________________                                        NONE*         150° C.                                                   100*         160° C.                                                   110*         160° C.                                                   140*         160° C.                                                   160*         170° C.                                                  180           190° C.                                                  240           250° C.                                                  250           250° C.                                                  280           230° C.                                                  300           200° C.                                                  325           220° C.                                                  350           220° C.                                                  ______________________________________                                         *Not an example of this invention.                                       

EXAMPLE 4 Corrosion Testing, 175° F. (79.4° C.)

The thermally treated products from Examples 1B and 2B were tested fortheir corrosion inhibition properties by the following procedure.

Corrosion inhibition of various samples was determined under conditionswhich simulate conditions that exist in oil and gas wells as follows. Abrine solution containing 89.89 percent deionized water, 9.62 percentsodium chloride, 0.305 percent calcium chloride and a 0.186 percenthydrated magnesium chloride complex was prepared. This brine solutionwas saturated under carbon dioxide purge until a pH of 3.8 was achieved.The solution was treated with sodium persulfate to remove oxygen. Thedesired corrosion inhibitor was added to the solution. About 720milliliters (ml) of this brine solution and 80 ml of kerosene treatedwith sodium persulfate were charged into a 32-ounce bottle. To thischarge was added enough hydrated sodium sulfide to generate a suitableamount of hydrogen sulfide (i.e., about 300 ppm hydrogen sulfide basedon total fluids).

Metal coupons of 1020 carbon steel were degreased with an inhibitedmethylchloroform, acidized with 16 percent hydrochloric acid, washed anddried. Each coupon weighed about 19 g. A metal coupon was placed in thebottom containing the brine, kerosene and ingredients as previouslydescribed. The bottle was capped and acetic acid was injected into thebottle through a septum. The bottle was placed on a vertically rotatingwheel held at 175° F. (79.3° C.) and the sample was rotated at 26 rpmfor 24 hours 86,400 s). The coupons were removed from the bottle,cleaned, washed, dried and reweighed and the percent protection affordedthem by the inhibitor is calculated as the percent protection by thefollowing formula: ##EQU1##

The weight loss is given to the nearest whole percent. The tests whereinno inhibitor is employed are for comparative purposes and are designatedas blanks.

The corrosion rates are also determined in milliinches per year (mpy)corrosion rates by the following formula: ##EQU2## Mg=milligramsd=density of 1020 carbon steel=7.86 g/ml

a=surface area (in².) of metal coupons

t=test time in hours

The amount of corrosion of untreated coupons was compared to couponswhich were tested in the presence of 100 ppm of each corrosion inhibitorsample. Results are presented in Table III for the thermally rearrangedacrolein/ethylenediamine oligomers prepared in Example 1-B.

                  TABLE III                                                       ______________________________________                                        INHIBITOR                                                                     Product From                                                                  Heat                                                                          Treatment at        Weight                                                    Indicated           Loss     %                                                Temp. °C.                                                                        Conc. ppm grams    Protection                                                                            MPY**                                    ______________________________________                                        No Inhibitor*                                                                           0         0.1879   0       71.0                                     No Heat   100       0.0351   81.3    13.3                                     Treatment*                                                                     125*     100       0.0357   81.0    13.9                                      135*     100       0.0402   78.6    15.7                                      150*     100       0.0344   81.7    13.9                                      162*     100       0.0325   82.7    12.5                                      170*     100       0.0261   86.1    10.8                                     180       100       0.0381   83.2    13.0                                     190       100       0.0477   74.6    16.8                                     200       100       0.0309   83.6    12.6                                     250       100       0.0423   77.5    14.8                                     ______________________________________                                         *Not an example of this invention.                                            **MPY is mils per year.                                                  

Results are presented in Table IV for the thermally rearrangedacrolein/mixture of tetraethylenepentamine, pentaethylenehexamine, andhexaethyleneheptamine oligomers prepared in Example 2-B.

                  TABLE IV                                                        ______________________________________                                        INHIBITOR                                                                     Product From                                                                  Heat                                                                          Treatment* at       Weight                                                    Indicated           Loss     %                                                Temp. °C.                                                                        Conc. ppm grams    Protection                                                                            MPY**                                    ______________________________________                                        No Inhibitor*                                                                           0         0.2804   0       109.8                                    No Heat   100       0.0394   81.2    15.2                                     Treatment                                                                      100*     100       0.0720   74.3    28.0                                      110*     100       0.0621   77.9    24.1                                      140*     100       0.0862   69.3    33.5                                      160*     100       0.0844   69.9    32.7                                     No Inhibitor*                                                                           0         0.2439   0       93.7                                     180       100       0.0389   84.1    15.0                                     192       100       0.0328   86.6    12.7                                     250       100       0.0257   89.5    9.9                                      No Inhibitor*                                                                           0         0.2412   0       92.6                                     280       100       0.0687   71.5    26.6                                     300       100       0.0490   79.7    19.1                                     325       100       0.0388   83.9    15.1                                     350       100       0.0446   81.5    17.0                                     ______________________________________                                         *Not an example of this invention.                                            **MPY is mils per year.                                                  

EXAMPLE 5 Preparation of Corrosion Inhibitor

Acrolein/ethylenediamine oligomers thermally rearranged at 250° C.(49.99 g) from example 1-B, Westvaco Diacid 1550 (76.91 g) andisopropanol (126.27 g) were weighed into a one liter 5 neck round bottomflask equipped with a condensing assembly, stirrer, thermometer andnitrogen inlet tube. The reactor contents were refluxed at 82° C. for 1hour (3600 s). A Barrett trap was attached to the reactor. One hour andeleven minutes (4260 s) later, all isopropanol had been removed by usingthe Barrett trap. The reactor contents were heated at 210° C. for 2hours 19 minutes (8340 s). Reactor contents (121.02 g) were cooled toless than 60° C. and then dissolved in isopropanol (196.45 g). Thisisopropanol solution was refluxed at 82° C. for 1 hour and 10 minutes(4200 s).

EXAMPLE 6 Preparation of Corrosion Inhibitor

Acrolein/ethylenediamine oligomers thermally rearranged at 250° C.(23.06 g) from Example 1-B, and 1-bromooctadecane (66.74 g) were weighedinto a 500 ml resin kettle equipped with a condensing assembly, stirrer,thermometer and nitrogen inlet tube. The reactor contents were heated at90° C. for 15 minutes (900 s) and then cooled to room temperature. 150ml xylene (181.54 g) was added to reactor contents. Reactor contentswere maintained at 75° C. for 35 minutes (2100 s). Reactor contents wereheated between 60°-110° C. for 2 additional hours (7200 s).

EXAMPLE 7 Preparation of Corrosion Inhibitor

Acrolein/mixture of 14 area % tetraethylenepentamine, 42 area %pentaethylenehexamine and 27 area % hexaethyleneheptamine oligomersthermally rearranged at 250° C. (20.8 grams) from Example 2-B,1-bromooctadecane (74.1 grams) and isopropanol (31.6 grams) were weighedinto a reactor of the type described in Example 6. Area % was determinedby gas chromatography. The reactor contents were stirred at 82.5° C. forone hour (3600 s). Isopropanol was removed at 90° C. by using a DeanStark trap.

EXAMPLE 8 Corrosion Testing

The corrosion inhibitors prepared in Examples 5, 6 and 7 were testedemploying the procedure of Example 4. The results are given in Table V

                  TABLE V                                                         ______________________________________                                                Concentration                                                                             Weight Loss                                                                              Percent                                        Inhibitor                                                                             ppm         grams      Protection                                                                            MPY                                    ______________________________________                                        None*   0           0.2725     0       105.2                                  Example 5                                                                             100         0.0328     88      12.3                                   Example 6                                                                             100         0.0281     90      10.8                                   None*   0           0.1700     0       65.5                                   Example 7                                                                             100         0.0178     89.5    6.8                                    ______________________________________                                         *Not an example of this invention.                                       

The data in Table V demonstrates that thermally rearranged,α,β-unsaturated aldehyde/amine oligomers reacted with a fatty carboxylicacid or organic halide exhibits excellent corrosion protection undersimulated down hole tests at 175° F.

EXAMPLE 9 Corrosion Testing, 350° F. (176.7° C.)

The performance of 100 ppm of a corrosion inhibitor sample also wastested in a 24 hour 350° F. (177° C.) wheel test containing 90 percentbrine/8 percent heptane/2 percent kerosene at 2,000 psi pressure (25°C.) with 10 percent hydrogen sulfide, 10 percent carbon dioxide and 80percent methane in a stainless steel pipe bomb. Results are presented inTable VI for the corrosion inhibitors prepared in Examples 5, 6 and 7.

                  TABLE VI                                                        ______________________________________                                                Concentration                                                                             Weight Loss                                                                              Percent                                        Inhibitor                                                                             ppm         grams      Protection                                                                            MPY                                    ______________________________________                                        None*   0           0.1443     0       135.0                                  Example 5                                                                             100         0.0382     74      35.7                                   Example 6                                                                             100         0.0311     79      29.1                                   Example 7                                                                             100         0.0289     80      27.0                                   ______________________________________                                         *Not an example of this invention.                                       

The data in Table VI demonstrates that thermally rearrangedα,β-unsaturated aldehyde/amine oligomers reacted with a fatty carboxylicacid or organic halide exhibits good corrosion protection undersimulated down hole tests at 350° F.

EXAMPLE 10

In a manner similar to Example 1, an EDA/acrolein oligomer was preparedand the final yellow viscous product had an amine hydrogen equivalentweight of 59.

This EDA/acrolein oligomer was functionalized with lauric acid in a 1liter reactor equipped with stirrer, thermometer, condenser, Dean-Starktrap, temperature controller, and nitrogen purge. To 50 grams of theEDA/acrolein oligomer was added 84.7 grams of lauric acid (whichtheoretically would react with 50% of the active amine hydrogens) and202.5 grams of isopropanol. The reactor contents were heated to 84° C.for 1 hour. The isopropanol was removed and the reactor contents wereheated to 210° C. for 4 hours. The reactor contents were cooled andisopropanol was added to make the final product 37% actives(EDA/Acrolein/Lauric Acid Adduct) in isopropanol.

EXAMPLE 11

In a manner similar to Example 10, oleic acid was reacted with theethylenediamine/acrolein oligomer such that 70% of the active aminehydrogens were theoretically reacted.

EXAMPLE 12

In a manner similar to Example 10, tall oil fatty acid was reacted withthe ethylenediamine/acrolein oligomer such that 50% of the active aminehydrogens were theoretically reacted.

EXAMPLE 13

In a manner similar to Example 10, a C₂₂ dimer acid from Westvaco(Westvaco diacid 1550) was reacted with the ethylenediamine/acroleinoligomer such that 70% of the active amine hydrogens were theoreticallyreacted.

EXAMPLE 14

In a manner similar to Example 10, a C₃₆ dimer acid from Emery (Empol1003) was reacted with the ethylenediamine/acrolein oligomer such that50% of the active amine hydrogens were theoretically reacted.

EXAMPLE 15

In a manner similar to Example 10, a napthenic acid was reacted with theethylenediamine/acrolein oligomer such that 75% of the active aminehydrogens were theoretically reacted.

EXAMPLE 16

In a manner similar to Example 10, a neodecanoic acid was reacted withthe ethylenediamine/acrolein oligomer such that 75% of the active aminehydrogens were theoretically reacted.

EXAMPLE 17

Into a reactor equipped with stirrer, thermometer, condenser, Dean-Starktrap, temperature controller, and nitrogen purge was charged 714 gramsof ethylenediamine (11.9 moles) and 547 grams methanol. Over a 3 hourperiod, 667.5 grams of acrolein (11.9 moles) diluted in 623.9 grams ofmethanol was added to the reactor contents at a temperature between 1°C. and 5° C. The methanol was removed via distillation and the reactorcontents diluted to 70% actives with isopropanol. The resulting producthad an amine hydrogen equivalent weight of 68.4.

35.4 grams of the above prepared EDA/acrolein oligomer, 60.0 grams ofmethanol, and 73.6 grams of 1-octadecylbromide were charged into areactor and refluxed at 70°-75° C. for 2 hours. The methanol was removedand the reactor contents heated to 210° C. for 6 hours.

EXAMPLE 18

56 grams of an EDA/acrolein oligomer prepared similarly to Example 1and34 grams of isopropanol were charged to a reactor and heated to 50° C.127 grams of benzyl chloride was added over a 1.3 hour period and thereactor contents refluxed for 1.75 hours at 84° C. Due to viscositybuildup during the reaction, 200 grams of isopropanol were added to thereactor contents to reduce viscosity. Chloride analysis determined thatthe reaction proceeded to at least 90% completion.

EXAMPLE 19

443.7 grams of a 37% actives (ethylenediamine/acrolein/tall oil fattyacid adduct) prepared similarly to Example 12 except that 75% of theactive amine hydrogens were theoretically reacted and the product wasdiluted in isobutanol and charged to a reactor. 115.3 grams of benzoylchloride was added to the reactor contents at ambient and the reactorcontents exothermed to 65° C. After exotherm subsided, the reactorcontents were heated to 90° C. for 6 hours.

EXAMPLE 20

The corrosion inhibitors prepared in examples 10 through 19 were testedemploying the procedures detailed in examples 4 and 9 at 100 ppm activeconcentrations. The results are given in Table VII.

                  TABLE VII                                                       ______________________________________                                                           Percent Protection                                         Inhibitor Hydrophobe     175° F.                                                                         350° F.                              ______________________________________                                        Ex. 10    Lauric Acid    79       82                                          Ex. 11    Oleic Acid     98       --                                          Ex. 12    Tall Oil Fatty Acid                                                                          95       85                                          Ex. 13    C22 Dimer Acid 87       86                                          Ex. 14    C36 Dimer Acid 86       88                                          Ex. 15    Napthenic Acid 91       86                                          Ex. 16    Neodecanoic Acid                                                                             97       82                                          Ex. 17    Octadecylbromide                                                                             96       --                                          Ex. 18    Benzyl Chloride                                                                              85       --                                          Ex. 19    Tall Oil Fatty Acid                                                                          94       74                                                    Benzoyl Chloride                                                    ______________________________________                                    

The data in Table VII demonstrates that thermally rearrangedα,β-unsaturated aldehyde/amine oligomers reacted with alkyl andcycloalkyl fatty acids with various carbon chain lengths or organichalides exhibits good corrosion protection under simulated down holetests at 350° F.

EXAMPLE 21

Into a jacket cooled reactor equipped with a condenser assembly,mechanical stirrer, nitrogen inlet tube, and thermometer were placed114.35 grams of ethylenediamine (EDA), 20.28 grams of a C₁₂ -C₁₄ fattymonoamine (P650), and 314.42 grams of methanol. 112.07 grams of acroleinwas added slowly to the reactor such that the reaction temperatureaveraged 1° to 5° C. After the addition was complete the methanol wasdistilled and the resulting product had an amine hydrogen equivalentweight of 67.3.

102.45 grams of this product was charged into a reactor along with561.94 grams of isopropanol. 413.91 grams of a C₂₂ dimer acid (Westvacodiacid 1550) was added and the reactor temperature was increased to 85°C. for 1 hour. The isopropanol was removed and the reactor temperaturewas increased to 210° C. for 4 hours. The resulting product was dilutedwith isopropanol to make the final product 43% actives. (EDA/P650/C₂₂dimer acid).

EXAMPLE 22

In a manner similar to Example 21, 1,3-propanediamine (PDA) was reactedwith acrolein in approximately a 6 to 1 mole ratio. The resultingproduct had an amine hydrogen equivalent weight of 58.01. 213.28 gramsof this product was subsequently reacted with 228.36 grams of the C₂₂dimer acid (Westvaco Diacid 1550) and heated to 220° C. for 3.5 hours.

EXAMPLE 23

In a manner similar to Example 21, ethylenediamine (EDA) and acroleinwere reacted in a 1 to 1 mole ratio and subsequently functionalized withWestvaco Diacid 1550 such that 70% of the active amine hydrogens weretheoretically reacted.

EXAMPLE 24

In a manner similar to Example 23, diethylenetriamine (DETA) was reactedwith acrolein in a 1 to 1 mole ratio and functionalized with WestvacoDiacid 1550 such that 70% of the active amine hydrogens weretheoretically reacted.

EXAMPLE 25

In a manner similar to Example 23, aminoethylpiperazine (AEP) wasreacted with acrolein in a 3 to 1.5 mole ratio (amine hydrogenequivalent weight=66.27) and functionalized with Westvaco Diacid 1550such that 70% of the active amine hydrogens were theoretically reacted.

EXAMPLE 26

In a manner similar to Example 23, triethylenetetramine (TETA) wasreacted with acrolein in a 1 to 1 mole ratio (amine hydrogen equivalentweight=55.05) and functionalized with Westvaco Diacid 1550 such that 70%of the active amine hydrogens were theoretically reacted.

EXAMPLE 27

In a manner similar to Example 23, aminoethylethanolamine (AEEA) wasreacted with acrolein in a 1.5 to 1 mole ratio (amine hydrogenequivalent weight=51) and functionalized with Westvaco Diacid 1550 suchthat 70% of the active amine hydrogens were theoretically reacted.

EXAMPLE 28

The corrosion inhibitors prepared in Examples 21 through 27 were testedemploying the procedures detailed in Examples 4 and 9 at 100 ppm activeconcentrations. The results are given in Table VIII.

                  TABLE VIII                                                      ______________________________________                                                            Percent Protection                                        Inhibitor Amine/Aldehyde  175° F.                                                                         350° F.                             ______________________________________                                        Ex. 21    P650/EDA/Acrolein                                                                             88       83                                         Ex. 22    PDA/Acrolein    91       --                                         Ex. 23    EDA/Acrolein    87       86                                         Ex. 24    DETA/Acrolein   94       --                                         Ex. 25    AEP/Acrolein    82       84                                         Ex. 26    TETA/Acrolein   94       83                                         Ex. 27    AEEA/Acrolein   86       85                                         ______________________________________                                    

The data in Table VIII demonstrates that thermally rearranged alkyl,cycloalkyl, alkanoldiamines, or blends of fatty amines with anycombination of these diamines when reacted with acrolein andfunctionalized with a C22 fatty acid exhibits good corrosion protectionunder simulated down hole tests at 350° F.

EXAMPLE 29

Into a reactor equipped with a condenser assembly, mechanical stirrer,nitrogen inlet tube, and thermometer was placed 50 grams of anethylenediamine/acrolein oligomer (prepared similarly to Example 1,amine hydrogen equivalent weight of 52.03), 138.38 grams of tall oilfatty acid, and 282.57 grams of isopropanol. The reactor contents wereheated to 85° C. for 1 hour and heated at 210° C. for 6 hours. Theproduct was diluted with isopropanol to 37% actives.

EXAMPLE 30

In a manner similar to Example 29, an E-100/acrolein oligomer with anamine hydrogen equivalent weight of 49 was reacted with tall oil fattyacid such that 50% of the active amine hydrogens were theoreticallyreacted.

EXAMPLE 31

In a manner similar to Example 29, an ethylenediamine/crotonaldehydeoligomer with an amine hydrogen equivalent weight of 71 was reacted withtall oil fatty acid such that 70% of the active amine hydrogens weretheoretically reacted.

EXAMPLE 32

In a manner similar to Example 29, an ethylenediamine/furfural oligomerwith an amine hydrogen equivalent weight of 62 was reacted with tall oilfatty acid such that 70% of the active amine hydrogens weretheoretically reacted.

EXAMPLE 33

In a manner similar to Example 29, a ethylenediamine/nonenal oligomerwith an amine hydrogen equivalent weight of 78 was reacted with tall oilfatty acid such that 70% of the active amine hydrogens weretheoretically reacted.

EXAMPLE 34

In a manner similar to Example 29, atetraethylenepentamine/cinnamaldehyde oligomer with an amine hydrogenequivalent weight of 64 was reacted with tall oil fatty acid such that70% of the active amine hydrogens were theoretically reacted.

EXAMPLE 35

In a manner similar to Example 29, a hexamethylenediamine/crotonaldehydeoligomer with an amine hydrogen equivalent weight of 55 was reacted withtall oil fatty acid such that 70% of the active amine hydrogens weretheoretically reacted.

EXAMPLE 36

The corrosion inhibitors prepared in Examples 29 through 35 were testedemploying the procedures detailed in Examples 4 and 9 at 100 ppm activeconcentrations. The results are given in Table IX.

                  TABLE IX                                                        ______________________________________                                                           Percent Protection                                         Inhibitor                                                                             Amine/Aldehyde   175° F.                                                                         350° F.                              ______________________________________                                        Ex. 29  EDA/Acrolein     95       85                                          Ex. 30  E-100/Acrolein   95       90                                          Ex. 31  EDA/Crotonaldehyde                                                                             97       78                                          Ex. 32  EDA/Furfural     95       71                                          Ex. 33  EDA/Nonenal      96       59                                          Ex. 34  TEPA/Cinnamaldehyde                                                                            99       57                                          Ex. 35  HMDA/Crotonaldehyde                                                                            98       56                                          ______________________________________                                    

The data in Table IX demonstrates that low molecular weight alpha, betaunsaturated aldehydes provide unexpectedly good corrosion protectionunder simulated down hole tests at 350° F. Acrolein and crotonaldehydeare the preferred alpha, beta unsaturated aldehydes. Additionally, highmolecular weight diamines such as hexamethylenediamine with 5 or morecarbon atoms per repeating unit provide less corrosion protection athigh temperatures than diamines with only two to four carbon atoms perrepeating unit.

What is claimed is:
 1. A new composition of matter which comprises theproduct resulting from thermally treating, at a temperature of fromabout 190° C. to about 350° C. for from about 10 minutes to about 48hours, the product resulting from reacting, in the presence or absenceof a suitable solvent,(A) acrolein, crotonaldehyde or a combinationthereof; and (B) at least one organic polyamine represented by theformula ##STR5## wherein R is a divalent saturated C₂ to C₄ aliphatichydrocarbon group; each R¹ and R² is independently hydrogen or asaturated alkyl amino or an alkyloxy group containing from 2 to about 4carbon atoms or when two adjacent R² groups are taken together, theyform a bridging alkylene radical containing 2 carbon atoms such that theR group containing 2 carbon atoms and two adjacent R² groups and twonitrogen atoms form a heterocyclic ring containing 4 carbon atoms and 2nitrogen atoms; x has a value from 1 to about 8; andwherein components(A) and (B) are employed in a mole ratio of (A) to (B) of from about 1:1to about 1:6.
 2. A composition of claim 1 wherein the polyamine isethylenediamine, diethylenetriamine, triethylenetetramine,tetraetylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, orany combination thereof.
 3. A new composition of matter which is thereaction product resulting from reacting at a temperature of from about25° C. to about 250° C. for a time sufficient to complete the reactionas determined by halide or residual acid number titrations,(I) theproduct resulting from thermally treating, at a temperature of fromabout 190° C. to about 350°L0 C. for from about 10 minutes to about 48hours, the product resulting from reacting, in the presence or absenceof a suitable solvent,(A) acrolein, crotonaldehyde or a combinationthereof; and (B) at least one organic diamine represented by the formula##STR6## wherein R is a divalent saturated C₂ to C₄ aliphatichydrocarbon group; each R¹ and R² is independently hydrogen or asaturated alkyl amino or an alkyloxy group containing from 2 to about 4carbon atoms or when two adjacent R² groups are taken together, theyform a bridging alkylene radical containing 2 carbon atoms such that theR group containing 2 carbon atoms and two adjacent R² groups and twonitrogen atoms form a heterocyclic ring containing 4 carbon atoms and 2nitrogen atoms; x has a value from 1 to about 8; and wherein components(A) and (B) are employed in a mole ratio of (A) to (B) of from about 1:1to about 1:6; and (II)(A) at least one saturated or unsaturated, cyclicor acyclic aliphatic mono- or polycarboxylic acid having from about 2 toabout 50 carbon atoms; or (B) at least one saturated or unsaturated,cyclic or acyclic aliphatic alkyl monohalide or alkyl polyhalide havingfrom about 2 to about 50 carbon atoms; or (C) a combination of (A) and(B); wherein components (I) and (II) are employed in quantities whichprovide from about 0.4 to about 1 equivalent of carboxyl or halide orboth groups from component (II) for each theoretically active aminohydrogen atom contained in component (I).
 4. A composition of claim 3wherein(a) components (II-A) or (II-B) or both each has from about 12 toabout 36 carbon atoms; and (b) components (I) and (II) are employed inquantities which provide from about 0.55 to about 0.85 equivalent ofcarboxyl and/or halide groups from component (II) for each theoreticallyactive amino hydrogen atom contained in component (I).
 5. A compositionof claim 4 wherein(a) components (II-A) or (II-B) or both each has fromabout 16 to about 20 carbon atoms; and (b) components (I) and (II) areemployed in quantities which provide from about 0.65 to about 0.75equivalent of carboxyl and/or halide groups from component (II) for eachtheoretically active amino hydrogen atom contained in component (I). 6.A composition of claim 4 wherein (a) component (I-B) is ethylenediamine,diethylenetriamine, triethylenetramine, tetraethylenepentaminepentaethylenehexamine, hexaethyleneheptamine or any combination thereof;and (b) component (II) is tall oil fatty acid, dimerized tall oil fattyacid, or any combination thereof.
 7. A composition of claim 5 wherein(a) component (I-B) is ethylenediamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine,hexaethyleneheptamine or any combination thereof; and (b) component (II)is high molecular weight fatty acid.
 8. A composition of claim 3 whereinthe reaction product of components (I-A) and (I-B) is an oligomer havingan amine hydrogen equivalent weight of from about 50 to about
 80. 9. Acomposition of claim 4 wherein the reaction product of components (I-A)and (I-B) is an oligomer having an amine hydrogen equivalent weight offrom about 50 to about
 80. 10. A composition of claim 5 wherein thereaction product of components (I-A) and (I-B) is an oligomer having anamine hydrogen equivalent weight of from about 50 to about
 80. 11. Acomposition of claim 6 wherein the reaction product of components (I-A)and (I-B) is an oligomer having an amine hydrogen equivalent weight offrom about 50 to about
 80. 12. A composition of claim 7 wherein thereaction product of components (I-A) and (I-B) is an oligomer having anamine hydrogen equivalent weight of from about 50 to about 80.